Potential of diet therapy on murine AIDS

Recently, a murine retrovirus (LpBM5 MuLV), which induces immunodeficiency syndrome in mice, termed MAIDS, has been found to have several features similar to those seen in human acquired immunodeficiency syndrome (AIDS). The present study was undertaken to compare the effects of 40% energy restriction (R) and/or ad libitum (AL) diets with vegetable [corn oil, (CO) (n-6)] or marine oil [menhaden fish oil (FO), (n-3)] as a source of dietary fats on the immune function and survival rate of C57BL/6 mice injected with the LpBM5 MuLV virus. Weanling mice were fed, throughout the study, either a 5% CO-, 5% CO(R)-, 20% CO- or 20% FO-based diet and 8 wk later the mice were injected with the LpBM5 MuLV (5 x 10⁵ plaque-forming units). The results revealed a significantly prolonged postinjected survival rate in the mice fed 20% FO and 5% CO(R) diets [5% CO = 131 ± 7 d; 5% CO(R) = 161 ± 13 d; 20% CO = 125 ± 6 d; 20% FO = 164 ± 14 d]. Immunological studies conducted 4 wk after injection revealed decline in both interleukin-2 production and proliferative response to mitogens in spleen cells of mice in all four dietary groups. However, this decline was less apparent in mice fed 5% CO(R) and 20% FO diets. The levels of prostaglandin E₂ (PGE₂) were found to be significantly lower only in animals fed 20% FO diets, whereas the levels of arachidonic acid (20:4) were found to be significantly lower in the spleen cells of groups fed 5% CO(R) and 20% FO diets and were higher in mice fed 5% CO and 20% CO diets. In conclusion, these findings indicate that changes induced by dietary (n-3) lipids and/or moderate energy restriction on the composition of lymphoid cell membranes can modulate the production or response of lymphokines, including immunosuppressive PGE₂, which appears to delay progression of the retroviral infection.